Modern manufacturing standards demand ever-increasing dimensional accuracy in a production setting. In order to meet these modern demands, such as, for example, assembly tolerances of less than one millimeter, efforts have been made to accurately determine the location of various manufacturing components in a three-dimensional space. Various dimensional metrology apparatus systems are available that provide a method in which to determine the dimensional location of manufacturing components inside a production setting.
One such example is a product provided by Metris USA, Inc., that offers an “indoor GPS” system as disclosed, for example, in U.S. Pat. Nos. 6,501,543 and 6,535,282. This system utilizes a plurality of infrared transmitters and a plurality of intelligent receivers where 3-D data requires a base reference for either known position data of a transmitter or a fixed receiver internal to a work surface. These indoor GPS systems, particularly the receivers, have proven to be expensive and fragile requiring the construction of complex communication infrastructure with several computers, Ethernet hubs, etc. For example, the receivers provided by Arc Second, Inc. are hardwired to a computer to transmit a signal received from a base transmitter. These complex receivers are fixed to targets, the location of which is determined by the indoor GPS system. The wiring associated with the receiver has proven expensive and difficult to work with in a production environment and makes it difficult to affix the receivers to production components.
Efforts to overcome some of these problems are associated with laser scanners available from Northern Digital, Eica Geosystems and others. Laser scanners include an infrared light transmitter and a retro-reflective prism, but are limited in application. There are also camera-based systems available from Leica Geosystems and others. However, all of these systems have proven to be cost-prohibitive, and not practicable for a production environment.
Therefore, there is a continuing need for a more rugged indoor metrology system that provides the necessary accuracy of modern manufacturing standards and eliminates the problems associated with the system set forth above.